Leading edge slot blowing on an open cavity in supersonic flow

Abstract

Supersonic flow over an open cavity can create intense pressure loads on the surfaces within the cavity. In order to combat these loads, the development of a control scheme to reduce them is becoming increasingly important for many engineering applications. The present study implements steady leading edge blowing through various configurations of spanwise-aligned rectangular leading edge slots. The effects of this control on the flow field were examined to determine the suppression mechanisms exploited by the leading edge blowing. The cavity studied here had a length-to-depth ratio of 6 and was placed in a freestream flow with a Mach number of 1.4. Actuators with one continuous slot and three and five segmented slots spanning the width of the cavity were installed at the leading edge. Surface pressure reductions of nearly 45% were achieved on the aft wall of the cavity using the 5-slot configuration. Velocity field measurements acquired through 2-component (streamwise-aligned measurement plane) and 3-component stereoscopic (cross-stream-aligned measurement plane) particle image velocimetry revealed the presence of streamwise-aligned vortices created by the segmented slots. These act to significantly alter the shear layer formed at the mouth of the cavity creating highly three-dimensional flow field features.

Mechanism of controlling supersonic cavity oscillations using upstream mass injection

“…Fluids 25, 086101 (2013) 19 2.54 1.0 1.8 5.18 × 10 6 /m Two perforated plates with 175 holes Wilcox 20 4-18 1.6-2.86 6.56 × 10 6 /m Mass transport through a porous cavity floor Lamp and Chokani 23 4.33 2D c 1.75 5.58 × 10 7 /m A steady or pulsed jet placed within the cavity below the front cavity lip Bueno et al 24 5-9 3 2 3.0 × 10 7 /m Six high frequency pulsed jets located just upstream of LE b Rizzetta and Visbal 25 5 0.5 1. 19 2 × 10 5 (L) Pulsed jet at a very high frequency located at LE b Ukeiley et al 26 5.5 3 1.5 1.0 × 10 5 (δ) Microjets and rectangular slot jets spaced along LE b Zhuang et al 6 5.16 0.87 2 2.8 × 10 6 (L) An array of supersonic microjets spaced along LE b Arunajatesan et al 27 5.6 0.55 1.5 1.0 × 10 5 (δ) A set of three slots spanning LE b Lusk et al 29 Among various active noise control methods, fluid mass injection is a promising candidate. Here a brief review is presented (Table I).…”

“…Using a cavity acoustics model developed by Sahoo and Annaswamy, 28 the role of microjets in cavity noise suppression was explained and predicted for a given noise control input. Lusk et al 29 experimentally studied cavity noise control with three different slot layouts placed close to the cavity leading edge. The results showed that, due to a stronger three-dimensionality being generated in the cavity shear layer, the layout with five slotted jets at the cavity leading edge was more effective than that with three slotted jets or one continuous jet.…”

Role of longitudinal vortices induced by jets in upstream boundary layer on suppression of cavity tone

“…It was shown that longitudinal vortices were induced by the jets and cavity tone was suppressed effectively. As shown in the previous research [1][2][3][4], it is revealed that upstream flow control was effective to reduce the cavity tone. However, reduction mechanism of cavity tone and effects of spacing of jets on cavity flow has not been clarified.…”

“…Therefore the development of reduction methods of the cavity tone is socially required. There have been many attempts to reduce the cavity tone by various methods such as plasma actuators, synthetic jets and blowing jets [1,2]. Huang et al [3] attempted to control cavity tone by plasma actuators in the upstream boundary layer and investigated the effects of the direction of the plasma actuators on suppression of the cavity tone.…”

Mode transition and oscillation suppression in supersonic cavity flow

“…The other method such as using a sub-cavity on the front wall of the cavity covered by a flat plate [20][21] has been proven to be effective. For active open-loop control, the mass injection is frequently utilized at the cavity leading edge or the upstream of it [22][23][24] . The existing results show that passive control and active open-loop control can be achieved for supersonic cavity flows, while active closed-loop control has not been used until now.…”